<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        *{
            margin: 0;
            padding: 0;
        }
        #box1 > ul{
            width: 800px;
            /* height: 200px; */
            background-color: antiquewhite;
             /* 弹性盒子的使用  */
             display: flex;
             /* 设置主轴的方向 
             column 为列
             row为行 可设置reserve反向
             */
             flex-direction: row;



        }
        #box1> ul >li{
            width:200px;
            height: 200px;
            list-style: none;

            /* 设置宽度不足时的收缩系数 */
            flex-shrink: 1;
        }
        #box1> ul >li:nth-child(1)
        {
            /* 设置子元素如何分父元素剩下的元素，如果有的话 */
            flex-grow: 1;
            background-color: aqua;
        }
        #box1> ul >li:nth-child(2)
        {
            flex-grow: 2;
            background-color: blueviolet;
        }
        #box1> ul >li:nth-child(3)
        {
            flex-grow: 3;
            background-color: tomato;
        }
    </style>
</head>
<body>
    <div id="box1">
        <ul>
            <li></li>
            <li></li>
            <li></li>
        </ul>
    </div>
</body>
</html>